From: Scott M Vermillion (scott_ccie_list@it-ag.com)
Date: Thu Oct 23 2008 - 14:53:04 ARST
Hi Yeo,
Do you have Dynamips? Even if you don't do your practice labs on it, the
capture function is invaluable for learning:
R1#debug ip packet det
IP packet debugging is on (detailed)
R1#ping 10.0.0.2 rep 1
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 10.0.0.2, timeout is 2 seconds:
!
Success rate is 100 percent (1/1), round-trip min/avg/max = 108/108/108 ms
R1#
*Mar 1 00:02:13.423: IP: tableid=0, s=10.0.0.1 (local), d=10.0.0.2
(FastEthernet1/0), routed via FIB
*Mar 1 00:02:13.427: IP: s=10.0.0.1 (local), d=10.0.0.2 (FastEthernet1/0),
len 100, sending
*Mar 1 00:02:13.431: ICMP type=8, code=0
*Mar 1 00:02:13.523: IP: tableid=0, s=10.0.0.2 (FastEthernet1/0),
d=10.0.0.1 (FastEthernet1/0), routed via RIB
*Mar 1 00:02:13.523: IP: s=10.0.0.2 (FastEthernet1/0), d=10.0.0.1
(FastEthernet1/0), len 100, rcvd 3
*Mar 1 00:02:13.527: ICMP type=0, code=0
R1#und all
All possible debugging has been turned off
R1#
From Wireshark:
No. Time Source Destination Protocol
Info
2 1.454000 10.0.0.1 10.0.0.2 ICMP
Echo (ping) request
Frame 2 (114 bytes on wire, 114 bytes captured)
Ethernet II, Src: cc:00:2f:80:00:10 (cc:00:2f:80:00:10), Dst:
cc:01:2f:80:00:10 (cc:01:2f:80:00:10)
Internet Protocol, Src: 10.0.0.1 (10.0.0.1), Dst: 10.0.0.2 (10.0.0.2)
Internet Control Message Protocol
Type: 8 (Echo (ping) request)
Code: 0 ()
Checksum: 0x7517 [correct]
Identifier: 0x0001
Sequence number: 0 (0x0000)
Data (72 bytes)
0000 00 00 00 00 00 02 09 30 ab cd ab cd ab cd ab cd .......0........
0010 ab cd ab cd ab cd ab cd ab cd ab cd ab cd ab cd ................
0020 ab cd ab cd ab cd ab cd ab cd ab cd ab cd ab cd ................
0030 ab cd ab cd ab cd ab cd ab cd ab cd ab cd ab cd ................
0040 ab cd ab cd ab cd ab cd ........
So it's everything but the L2 encapsulation - it includes the IP header.
Cheers,
Scott
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Kelvin Yeo
Sent: Thursday, October 23, 2008 9:36 AM
To: 'Cisco certification'
Subject: Debug IP Packet 'len'
hi guys
i'd very much appreciate any help with a question - in the output of the
'debug ip packet detailed' command below, is the packet length shown (len
1552) the packet length iNCLUDING the IP packet header or EXCLUDING the
IPpacket header?
r1#debug ip pack det
IP packet debugging is on (detailed)
r1#01:04:59: IP: s=192.168.1.1 (Serial0/0), d=192.168.2.2
(Serial0/1),g=192.168.2.2, len 1552, forward, proto=50
Rgs,
Yeo
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Version: 7.5.524 / Virus Database: 270.6.13/1642 - Release Date: 29/08/2008
18:12
Internal Virus Database is out-of-date.
Checked by AVG.
Version: 7.5.524 / Virus Database: 270.6.13/1642 - Release Date: 29/08/2008
18:12
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